182 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
gives a summary of all these researches, and in the present paper 
Ballowitz extends his observations to Coleoptera. 
In beetles there are two main types of spermatozoa, connected, how- 
ever, by intermediate forms. There is a double-tailed type already 
described by Biitschli and v. la Yalette St. George, and there are others 
which are single-tailed. Biitschli showed that in the double spermato- 
zoon, one tail filament is straight and stiff, the other is undulating 
and contractile. Ballowitz describes this type in Hylobius, Chrysomela, 
Calathrus , &c., and shows that the straight or supporting portion of the 
tail is elastic, but somewhat stiff, resistant to reagents and without any 
fibrillar structure, while the contractile fringe consists of an extremely 
complicated system of fibrils. The single-tailed type of spermatozoon, 
as seen e. g. in J Ielolontha and Hydrojphilus , has no supporting fibres. 
The tail is twisted in a spiral, corresponds to the contractile fringe of 
the double type, and exhibits a complicated fibrillar structure. There 
is no need to attempt explaining how these spermatozoa, carefully 
macerated, &c., divide into peripheral, median, and fringing fibres, and 
these again into fibrils, for the details are unintelligible without the 
figures. The main point is the further demonstration of fibrillation 
in eminently contractile structure. Very interesting are Ballo witz’s 
descriptions of the movements of the spermatozoa, e.g. how the fringed 
type works its way like the screw of a steamer. Raising the temperature 
of the medium from 20°-30° C. quickens movement ; the optimum is from 
80°-35° C. ; above this towards 40° C. the power of movement is lost. 
Strong movements, especially in warmth, tend to produce a fibrous 
disruption of the spermatozoon. It is even observed that one of the 
contractile fibres of a complex spermatozoon may move independently of 
the others. 
Parthenogenesis of Ants induced by heightened temperature.* — 
Herr E. Wasmann was able during three successive winters to induce 
parthenogenesis in the workers of Formica sanguinea and their helpers 
F.fusca , by artificially warming the nests. On one day as many as 
twelve workers of F. sanguinea were seen laying eggs. Most of them 
were large workers, but small forms were also affected, and the smaller 
the ant the more tedious was the egg-laying. Sometimes, however, they 
got obstetric assistance from others. Of the many hundreds of eggs thus 
laid none attained full development ; as eggs or as larvaa all were 
devoured by the ants. It remains to corroborate these important 
physiological experiments by histological examination of the ovaries to 
see how their development is affected. 
Can Ants hear?f — Herr E. Wasmann relates an interesting fact 
which he observed in studying a small colony of Formica rufa. The 
upper glass plate of a formicarium like that of Lubbock’s had been 
cracked and mended with sealing-wax. When the dry sealing-wax was 
scratched with a needle, the ants suddenly raised their antennae, moved 
rapidly, and sought to inspect the glass plate. They did so often, but paid 
little heed if the wax was rubbed with some smooth object which did not 
produce the small shrill sound caused by the needle. As Forel does not 
believe that ants hear, and as Lubbock’s opinion that they do is based 
* Biol. Centralbl., xi. (1891) pp. 21-3. t T. c., pp. 26-7. 
